Sodium Hypochlorite (NaClO) is typically used as a disinfectant or as a “bleach”. It is also used to sanitise water at a water treatment works. In water treatment plants Sodium Hypochlorite is produced on site using a continuous process electrolytic cell. Sodium Hypochlorite can also be used to disinfect the water of swimming pools, which need to be treated regularly with disinfectants to ensure the water is of a suitable quality. Typically, Sodium Hypochlorite is purchased in solid crystalline form and used for disinfecting the water used in swimming pools.
It is also common for water to be stored in storage tanks in food production factories and supermarkets, for example, so that it can be utilised in the event of an interruption in the mains water supply. It is advantageous to maintain a store of water because an interruption in the mains water supply may cause a break in production, which is costly. Water delivered to a factory or supermarket by the mains water supply can, at least in the United Kingdom, be assumed to be suitably clean for use in the production of food, for example. It is less common for the water stored in storage tanks to be treated prior to use, as it is assumed that the quality of the water has not decreased during storage. However, the water that is stored in the storage tanks may be standing for a substantial time and thus it is possible that the stored water may become unsuitable for use in certain production processes.